Coordinate positioning machine

A coordinate positioning machine comprising a drive frame and a metrology frame, the drive frame comprising a drive arrangement for moving a moveable structure around a working volume of the machine, and the metrology frame comprising a metrology arrangement for measuring the position of the structure within the working volume, wherein the metrology arrangement is a hexapod metrology arrangement and the drive arrangement is a non-hexapod drive arrangement, wherein the metrology frame has a coefficient of thermal expansion that is lower than that of the drive frame, thereby causing an extra thermal expansion or contraction of the drive frame compared to the metrology frame, and wherein the drive frame is coupled to the metrology frame via a coupling arrangement which is adapted to prevent at least some of the extra thermal expansion or contraction of the drive frame, or at least some distortion associated with the extra thermal expansion or contraction of the drive frame, from being transferred to the metrology frame.

A coordinate positioning machine comprising a drive frame and a metrology frame, the drive frame comprising a drive arrangement for moving a moveable structure around a working volume of the machine in fewer than six degrees of freedom, and the metrology frame comprising a metrology arrangement for measuring the position of the structure within the working volume in more degrees of freedom than the drive arrangement, wherein the metrology frame has a coefficient of thermal expansion that is lower than that of the drive frame, thereby causing an extra thermal expansion or contraction of the drive frame compared to the metrology frame, and wherein the drive frame is coupled to the metrology frame via a coupling arrangement which is adapted to prevent at least some of the extra thermal expansion or contraction of the drive frame, or at least some distortion associated with the extra thermal expansion or contraction of the drive frame, from being transferred to the metrology frame.

A coordinate positioning machine comprising a drive frame and a metrology frame, the drive frame comprising a drive arrangement for moving a moveable structure around a working volume of the machine, and the metrology frame comprising a metrology arrangement for measuring the position of the structure within the working volume, wherein the metrology arrangement comprises a plurality of measurement transducers in a parallel arrangement for providing a corresponding respective plurality of measurements from which the position of the moveable structure is determinable, and wherein the drive arrangement comprises a plurality of actuators in a parallel arrangement of a different type to that of the metrology arrangement, wherein the metrology frame has a coefficient of thermal expansion that is lower than that of the drive frame, thereby causing an extra thermal expansion or contraction of the drive frame compared to the metrology frame, and wherein the drive frame is coupled to the metrology frame via a coupling arrangement which is adapted to prevent at least some of the extra thermal expansion or contraction of the drive frame, or at least some distortion associated with the extra thermal expansion or contraction of the drive frame, from being transferred to the metrology frame.